The invention relates generally to imaging of an object, and more specifically to visualizing an image that is registered with a pre-acquired volume image data set.
Image registration finds wide application in medical imaging, video motion analysis, remote sensing, security and surveillance applications. Further, the process of finding the correspondence between the contents of the images is generally referred to as image registration. In other words, image registration typically entails finding a geometric transform that non-ambiguously links locations and orientations of the same objects or parts thereof in the different images. More particularly, image registration includes transforming the different sets of image data to a common coordinate space. The images may be obtained by different imaging devices or alternatively by the same imaging device but at different imaging sessions or time frames. As will be appreciated, in the field of medical imaging, there has been a steady increase in the number of imaging sessions or scans a patient undergoes. Images of a body part may be obtained temporally from the same imaging modality or system. Alternatively, in multi-modal imaging, images of the same body parts may be captured via use of different imaging modalities such as an X-ray imaging system, a magnetic resonance (MR) imaging system, a computed tomography (CT) imaging system, an ultrasound imaging system or a positron emission tomography (PET) imaging system.
In medical applications, registration of images is confronted by the challenges associated with patient movement. For example, due to either conscious or unconscious movement of the patient between two scans obtained either via the same imaging modality or otherwise, there exists an unpredictable change between the two scans. Unfortunately, this change in position leads to misalignment of the images. Additionally, patient position may vary depending on the imaging modalities used for multi-modal scanning. For example, a patient is generally positioned in the prone position (i.e., lying face down) for a magnetic resonance imaging (MRI) scanning session and may be in the supine position (i.e., lying face up) during a colon exam scanning session thereby creating inherent registration problems.
Volume-guided ultrasound is an application in which an ultrasound image may be registered to a previously acquired (pre-acquired) image volume. The pre-acquired volume data set may include a CT image data set, an MR image data set, a PET image data set, or an ultrasound image data set, for example. As will be appreciated, it may be desirable to simultaneously display the ultrasound image data and the corresponding slices or rendering from the pre-acquired volume image data set.
Previously conceived solutions to display the ultrasound image and the corresponding slices or rendering from the pre-acquired volume image data set include displaying the ultrasound image and a corresponding slice in a side-by-side configuration on a display of an imaging system. However, if the two images are displayed side-by-side then the screen size may limit the size of the displayed images. Alternatively, if the side-by-side display of the two images includes a larger display of the images, then partial clipping of the images may be required in order to accommodate the two images within a limited size of the display. Further, the pre-acquired image volume data set may include a substantially large volume of information. Consequently, if the two images are displayed in their entirety and in the same scale, then the displayed images are relatively small. Alternatively, the pre-acquired image volume image may be clipped off, however, the context of the currently displayed slice may not be easily understood.
There is therefore a need for a design of a method and system capable of efficiently visualizing a registered ultrasound image and a corresponding pre-acquired image volume data set in a side-by-side configuration. Further, there is also a need for a design of a method and system capable of visualizing an ultrasound image and a pre-acquired image volume data set that are overlaid on one another. In particular, there is a significant need for a design of a method and a system for visualizing registered images that enhances clinical workflow and facilitates superior diagnosis.